Designing Vitamin D3 Formulations: An In Vitro Investigation Using a Novel Micellar Delivery System

Abstract

Vitamin D is an essential nutrient with important immunomodulatory properties. As a fat-soluble compound, Vitamin D (and its D3 form) is immiscible with water, which presents challenges to absorption. In an in vitro setting, the current study characterizes novel micellar formulations of Vitamin D3 designed to improve absorption. Techniques used to evaluate and compare the micellar formulations against a non-micellar formula include the following: cryo-SEM to determine morphology; laser diffraction to determine particle size and distribution; zeta potential to determine stability of the particles; solubility assays to determine solubility in water and gastrointestinal media; and Caco-2 cell monolayers to determine intestinal permeability. Results show advantageous features (particle size range in the low micrometres with an average zeta potential of −51.56 ± 2.76 mV), as well as significant improvements in intestinal permeability, in one optimized micellar formula (LipoMicel®). When introduced to Caco-2 cells, LipoMicel’s permeability was significantly better than the control (p < 0.01; ANOVA). Findings of this study suggest that the novel micellar form of Vitamin D3 (LipoMicel) has the potential to promote absorption of Vitamin D3. Thus, it can serve as a promising candidate for follow-up in vivo studies in humans.